When mounting a machine member, e.g. a bearing on a shaft, it is possible either to mount the machine member directly on the shaft by means of a press fit, a shrinkage fit or a glue joint, or by means of a clamping sleeve having tapering grooves or threads, whereby the clamping force around the shaft is caused mainly by axial displacement of the machine member along the clamping sleeve.
Depending on which type of attachment is chosen, e.g. in connection with a ball bearing, different types of inner race rings must be available for the bearing. For mounting directly upon the shaft, which might be cylindrical or tapering, inner race rings having a cylindrical bore or a tapering bore, respectively, shall be used. At mounting with sleeve are used inner race rings having tapering portions corresponding to those of the clamping sleeve. Furthermore, the bearing must be increased by one size. Manufacture and stockkeeping of several different standard types of the same element, i.e. in this case bearing inner race rings, of course implies a big cost.